Tuyere and bosh cooling system



Sept. 1l, 1962 L. D. HOADLEY ET AL TUYERE AND BosH COOLING SYSTEM Filed Sept. 24, 1959 BY RICHRD H. MORGAN ATTORNEYS United States Patent O 3,053,524 'IUYERE AND BOSH COOLING SYSTEM Lemuel D. Headley, Dearborn, Robert J. McGrath, Wyandotte, and Richard H. Morgan, Trenton, Mich., asgrllors to National Steel Corporation, a corporation of e aware Filed Sept. 24, 1959, Ser. No. 842,114 3 Claims. (Cl. 266-32) The invention relates to an improved temperature control structure for blast furnace walls, more specifically, an improved system for cooling the tuyere breast and bosh regions of a blast furnace.

Blast furnace structure can generally be divided into three main parts: 1) a lower section known as the hearth, the bottom portion of which serves as a receptacle for the molten metal and slag; (2) an intermediate section known as the bosh, `an inverted frustrum of a cone located immediately above the hearth; and (3) an upper section known as the shaft or stack. The hot blast is supplied to the blast furnace through the tuyeres. The tuyeres, usually approximately twenty in number, are distributed symmetrically about the upper portion of the hearth. The refractory materials employed in the different sections of the furnace can vary with conditions to be met in the area. The temperature in the tuyere region is usually the highest found in the blast furnace and is `approximately 3600 F.; the middle bosh region temperature is approximately 3000 F.; the upper bosh region is approximately 2800 F.; and the lower portions of the stack are at approximately 2100 F. In the past, the common refractories used in the hotter regions of the furnace were the thick-wall type and cooling of the refractory was effected by imbedding hollow cooling plates in the thick refractory wall at regular intervals. More recently, thin-wall refractories made of carbon have been used in these hotter portions of the blast furnace structure. When the thin-wall refractories are employed a heavy steel-plate jacket surrounds the refractories, lending support to the blast furnace structure. Cooling such blast furnace structure, especially in the tuyere and bosh areas,

as presented complex problems beyond the scope of conventional cooling means.

It is therefore an important object of the invention to provide improved cooling for the tuyere breast and bosh regions of blast furnaces employing thin-wall refractories.

In the accompanying drawings:

FIGURE l is a view in elevation of a portion of the cooling system for the tuyere breast land bosh areas of a blast furnace, in accordance with the invention,

FIGURE 2 is a view in vertical section of a portion of a blast furnace wall between `the hearth and stack sections taken on the line 2--2 of FIGURE l, and

FIGURE 3 lis a partial horizontal section of the cooling system of a portion of the bosh area taken on the line 3-3 of FIGURE 1.

In the blast furnace illustrated in FIGURES 1 to 3 inclusive, thin wall refractories 4 are used in the tuyere region of the furnace. The refractories '4 are supported in the region of the tuyeres 5 by the tuyere breast plate 6. A steel jacket 7, herein termed a bosh plate, supports the thin-wall bosh refractories 8. The stack area of the furnace has thick wall refractories 9 With cooler plates 10 imbedded therein. The tuyere breast cooling assembly, designated generally as 11, is welded to the tuyere breast plate 6. The bosh cooling assembly designated generally 12, is welded to the bosh plate 7. In this manner the tuyere breast plate and the bosh plate act as part of the furnace cooling system.

Referring to FIGURE 1, it can be seen more clearly how the tuyere breast cooling assembly and bosh cooling assembly cooperate to control the temperature of the entire tuyere and bosh areas of the furnace Wall. Adjacent to each tuyere 5 the tuyere breast area is cooled by two symmetrically disposed 'tuyere breast cooling members or elements 13 and 14 to the left and right respectively of the tuyere. In the interest of brevity only tuyere breast cooling member 13 will be described in detail: member `13 is divided into three sections, section 15 below the tuyere level, vertical section 16 at the side of the tuyere, and section 17 above the tuyere level. Each section is made up of a U-shaped element with the legs welded to the tuyere breast plate. The sections below and above the tuyere levels 15 and 1'7 are closed at the ends and include baffle plates 18 and 19 respectively. Section 16 is an open ended U-shaped element connecting openings in the legs of sections 15 and 17. Cooling fluid enters the member v13 at inlet 2t)` and follows the tortuous path indicated by the flow arrows and exists from the upper portion of section 17 via the outlet 21. The structure of the tuyere breast cooling member 14 is identical to that of the tuyere breast cooling member 13 but it is symmetrically reversed on the right side of tuyere 5. The structure of tuyere breast cooling members 13` and 14 is repeated for each tuyere around the circumference of the furnace.

The bosh cooling assembly includes cooling elements 22 which are distributed about the circumference of the furnace at the bosh area. These bosh cooling elements are elongated channel shaped elements extending between the tuyere region and the stack region of the furnace with their legs welded to the bosh plate and their ends closed. Each bosh cooling element 22 about the circumference of the furnace has a lower inlet 23, and an upper outlet 24.

In FIGURE 1 it can be seen that individual tuyere breast cooling elements are connected in a special arrangement to individual bosh cooling elements via individual conduit means. Thus, tuyere breast cooling member 13 is connected by pipe 25 to a bosh cooling element 22 circumferentially displaced relative to Ituyere breast cooling member 13 and preferably relative to the tuyere cooled by this same member 13. The cross sectional areas of members 13 and 14 and elements 22 are such that the desired velocity of water is maintained throughout each path through them.

In the operation of the improved cooling system of the invention, the cooling medium, usually water, travels sequentially through a tuyere breast cooling member, a conduit and a bosh cooling element. For example, water enters tuyere breast cooling member 13 through the inlet 2.0, follows a tortuous path around the baffle 18, travels upwardly lalong the tuyere 5 through section 16, passes through section 17 following the tortuous path defined by bafe 19, and exits through outlet 21; pipe 25 connects outlet 2.1 with inlet 23- of a bosh cooling element 22; the cooling medium then travels upwardly through the bosh cooling element 22 to an outlet 24 located at the upper region of the bosh cooling element. Each tuyere breast cooling member has 1a drain and clean-out plug 27 and each bosh cooling element has drain and clean-out plugs 28 and 29 located for proper drainage and cleaning of the respective elements as needed.

The cooling system of the invention has peculiar advantages in blast furnace operation. In the blast furnace, molten and other particulate matter drain downwardly through the blast furnace in contact with the refractory Walls. By having the tuyere breast cooling elements and the bosh cooling elements circumferentially displaced around the blast furnace, itis possible to clean one series of cooling elements without developing a hot spot or damaging the furnace lining. The circumferential displacement ofthe series-connected cooling elements results in the vertical path traveled by furnace material crossing two cooling zones in the furnace. Portions of this vertical path `are cooled by elements from separate seriesconnected flow passages. In this way, an extended portion of the vertical path traveled by the particulate matter is never Without cooling. Further, an advantage of employing the plurality of cooling passages disclosed is that hot spots, due to some phenomenon in the furnace operation or a defect in the cooling system, can be readily and accurately located by an observation of the temperature of the exit cooling medium and remedial action can be directed to the area Where needed. Finally, by passing the water through both tuyere breast coolers and bosh coolers in series, full advantage of the cooling action of the minimum amount of water can be obtained while maintaining a check on the furnace wall temperature in a localized Zone throughout the circumference of the furnace.

It is to be understood that the form of the invention herewith shown and described, is to be taken as a preferred example and that various changes in the shape, size, and arrangement of parts may be resorted to without departing from the spirit of the invention. Reference will be had to the subjoined claims for a definition of the limits of the invention.

What is claimed is:

1. In combination with a blast furnace Wall having a thin wall type carbon refractory lining with steel jacketed tuyere `and bosh areas, a temperature control system for the tuyere and bosh areas comprising a plurality of tuyere breast cooling elements covering the tuyere area of the furnace,

a plurality of bosh cooling elements covering the bosh area of the furnace,

a plurality of conduits connecting individual tuyere breasts in series with individual bosh cooling elements to form separate series connected cooling passages in which the individual tuyere breast cooling elements and the individual bosh cooling elements connected in series do not lie in the same vertical plane normal to the blast furnace wall.

2. In combination with a blast furnace wall having a thin-wall type refractory lining and steel jacketed tuyere and bosh areas, -a cooling system which is externally mounted on the steel jacketed areas comprising a plurality of tuyere breast cooling elements Welded to the steel jackets at the tuyere area of the furnace, a plurality of bosh cooling elements welded to the steel jacket at the bosh area of the furnace, and 5 conduit means connecting tuyere breast cooling elements in series with bosh cooling elements to define coolant passageways extending in series over the tuyere breast and bosh areas in which the series connected tuyere breast and bosh cooling elements do not lie in the same vertical plane normal to the blast furnace wall. 3. In combination with a blast furnace wall including a tuyere area and a bosh area located thereabove, a ternperature control system for tuyere and bosh areas of the furnace comprising tuyere breast cooling elements having multiple sections dening a coolant ow path around each blast furnace tuyere, a plurality of bosh cooling elements disposed around the bosh area of the furnace, and

conduit means connecting individual tuyere breast cooling elements in series with individual bosh cooling elements to define separate series connected coolant ow paths in which the individual tuyere breast cooling elements and individual bosh cooling elements do not lie in the same vertical plane normal to the blast furnace Wall.

References Cited in the le of this patent UNITED STATES PATENTS 277,638 Wendt May 15, 1883 320,586 Probert June 23, 1885 499,188 Giroux June 6, 1893 591,524 Burgers oct. 12, 1897 614,381 Gaines Nov. 15, 1898 769,665 McGee Sept. 6, 1904 2,396,976 Whitehurst Mar. 19, 1946 2,697,598 Affleck Dec. 21, 1954 FOREIGN PATENTS 339,972 Great Britain Dec. 17, 1930 

